Non-oriented electrical steel sheets are materials used for iron cores of electrical equipment. To increase the efficiency of electrical equipment, it is effective to lower the iron loss of electrical steel sheets. In order to reduce the iron loss, it is effective to add an element having a large specific resistance, such as Si, Al, or Mn. Among these, Al is suitable for achieving both iron loss reduction and blanking workability improvement since it causes a large increase in specific resistance, yet a small increase in strength.
However, Al-added steel has the problem of poor recyclability. Specifically, use of Al-added steel as scrap material causes deterioration of electrodes of the electric furnace, leading to lower recyclability of products.
For better recyclability, it is thus preferable to reduce Al in steel sheets, and there is a demand for electrical steel sheets having excellent magnetic properties even with low Al concentrations.
To address these issues, for example, JP2004277760A (PTL 1) proposes a technique for obtaining excellent magnetic properties by controlling Cu sulfides in low-Al steel.